A conventional display device of this kind is shown in FIGS. 3 and 4, where a slider 2 is mounted on a panel 1 so as to be horizontally movable. A knob 3 is put over the front end of the slider 2. A light-conducting body 4 for displaying the operation of the knob is received above the slider 2, and tapers off toward the knob 3. The knob 3 is provided with a hole 5 at a relatively high position. The light-conducting body 4 extends through the hole 5, and its front end is exposed to form an illuminator A for displaying the operation of the knob. Another light-conducting body 6 for displaying the position of the knob is received below the slider 2. The width of the body 6 is uniform as shown in FIG. 3. A face plate 9 is fitted in a hole 8 formed in the knob 3. The light-conducting body 6 extends outwardly of the panel 1, and the face plate 9 is attached to the outer end of the body 6 to form an illuminator B for displaying the position of the knob. Lamps 10 and 11 are mounted to display the operation and the position, respectively. A sliding switch 12 is provided to light up the lamp 10. An operated rod 13 is disposed opposite to the slider 2. The face plate 9 is marked with symbols 7 that indicate the operation.
The operation of the device for displaying the operation of the knob 3 is now described. The lamp 11 for indicating the position is lit up in the night or when the inside of the automobile is dark. The light emanating from the lamp 11 is projected into the light-conducting body 6 for displaying the position, so that the illuminator B lights up. As a result, the driver can see the position of the knob 3 through the face plate 9, even if the inside of the automobile is dark. Under this condition, the knob 3 is in its non-operative position.
In order to shift the knob 3 to its operative position, the knob is depressed as indicated by the arrow, i.e., moved to the left as viewed in FIG. 3. After the knob 3 comes to a halt at a given position, the slider 2 moves together with the knob 3. Then, the left end of the slider 2 pushes the rod 13 of the sliding switch 12, turning on this switch 12. This in turn lights up the lamp 10 for displaying the operation. The light emanating from the lamp 10 is projected into the light-conducting body 4, so that the illuminator A for displaying the operation lights up. As a result, the driver ascertains from outside of the panel 1 that the knob 3 is in its operative position.
When the knob 3 returns to its non-operative position, the rod 13 of the switch 12 returns to its original right position. Then, the light 10 and the illuminator A go out.
In the display device constructed as described above, both the illuminator B for displaying the position and the illuminator A for displaying the operation are installed on the knob 3. That is, both the position and the operation are displayed on the knob 3. Therefore, it is difficult to miniaturize the knob 3. Also, neither the illuminator A nor B can be made large, because they are installed in a limited area. Further, when the knob 3 is depressed to its operative position, the illuminator A for displaying the operation is hidden by the finger. This makes it difficult to ascertain that the operation is completed.